diff --git a/SharepointToolbox/Core/Messages/LanguageChangedMessage.cs b/SharepointToolbox/Core/Messages/LanguageChangedMessage.cs
new file mode 100644
index 0000000..f32fd00
--- /dev/null
+++ b/SharepointToolbox/Core/Messages/LanguageChangedMessage.cs
@@ -0,0 +1,8 @@
+using CommunityToolkit.Mvvm.Messaging.Messages;
+
+namespace SharepointToolbox.Core.Messages;
+
+public sealed class LanguageChangedMessage : ValueChangedMessage<string>
+{
+    public LanguageChangedMessage(string cultureCode) : base(cultureCode) { }
+}
diff --git a/SharepointToolbox/Core/Messages/TenantSwitchedMessage.cs b/SharepointToolbox/Core/Messages/TenantSwitchedMessage.cs
new file mode 100644
index 0000000..81b1a2e
--- /dev/null
+++ b/SharepointToolbox/Core/Messages/TenantSwitchedMessage.cs
@@ -0,0 +1,9 @@
+using CommunityToolkit.Mvvm.Messaging.Messages;
+using SharepointToolbox.Core.Models;
+
+namespace SharepointToolbox.Core.Messages;
+
+public sealed class TenantSwitchedMessage : ValueChangedMessage<TenantProfile>
+{
+    public TenantSwitchedMessage(TenantProfile profile) : base(profile) { }
+}
diff --git a/SharepointToolbox/Core/Models/OperationProgress.cs b/SharepointToolbox/Core/Models/OperationProgress.cs
new file mode 100644
index 0000000..d53b761
--- /dev/null
+++ b/SharepointToolbox/Core/Models/OperationProgress.cs
@@ -0,0 +1,7 @@
+namespace SharepointToolbox.Core.Models;
+
+public record OperationProgress(int Current, int Total, string Message)
+{
+    public static OperationProgress Indeterminate(string message) =>
+        new(0, 0, message);
+}
diff --git a/SharepointToolbox/Core/Models/TenantProfile.cs b/SharepointToolbox/Core/Models/TenantProfile.cs
new file mode 100644
index 0000000..eac90a1
--- /dev/null
+++ b/SharepointToolbox/Core/Models/TenantProfile.cs
@@ -0,0 +1,8 @@
+namespace SharepointToolbox.Core.Models;
+
+public class TenantProfile
+{
+    public string Name { get; set; } = string.Empty;
+    public string TenantUrl { get; set; } = string.Empty;
+    public string ClientId { get; set; } = string.Empty;
+}